I was warned by several here that this would happen and they were right. Lesson learned...go with minimal twist with these VLDs. Using a 6 groove should help too.

I'm just trying to learn and understand. And I understand the twist being too fast. But what about the number of grooves? It would seem to me that 6 groove rifling would exert more strain on the bullet jacket, thus aiding failure in flight. -- gr8whyt

According to the people that said a 3 groove would be part of the problem said the width of the lands combined with the roughness of a partially worn throat would weaken the jacket material enough to cause bullet failure when combined with such a fast twist.

Any idea of the RPMs of a bullet leaving a 7mm 1 in 7 twist compared to a commonly used 1 in 9?
formula: MV x 720/twist
180 Berger VLD @ 3000 from 1 in 7 = 308,571 RPMs
180 " " @ 3000 from 1 in 9= 240,000 RPMs

Speaking of RPMs: that rifle now shoots the 140 accubond @ 3400 fps from that 30" barrel. Tried 160s accubonds but first attempts were poor. May try again this spring.

140 Accubond 1in7 @ 3400 = 349,714
compared to 1 in 9 @ 3400 = 272,000
I didn't use it for coues wt this year but have been wondering how the extra RPMs might effect an animal.

We've been using the 115 Hunting VLD, 25-06, loaded up to 3150 with R-22, 56.4 grains for 4 years and here in Missouri we don't need 300 yd shots, longest on large 10point was 235 yds. We have learned that this bullet ruins good meat, so have been making successful neck shots in 8 of the last 10 deer....

Last year the big 10 point was broadside, a neck shot put him into a summersalt, head dropped and nearly stuck his rack in the ground! Entry holes small, exit from neck growing to 4-6" diameter damage. All but one kill have been "Drop Dead Now".

My step son uses a cheap single shot, grandson a Rem 700, and I have a Mauser/custom barrel...all are 1:10 twist.

Got some "Target" VLD's we'll use for sighting in, but will stick with Hunting as they have proven deadly.

This is straight from Walt Berger and Eric Stecker. Both bullets use J-4 jackets, but the Hunting bullet uses the original THIN jacket, while the target buillet uses A thicker jacket- which will not expand reliably at longer distances. Good shooting...James

"In regards to all of our other Target and Hunting bullets the Target bullets have a thicker jacket to withstand rougher conditions. However, the only bullet in the entire Berger line that is exactly the same in every way in both the Target and Hunting version is the 25 cal 115 gr VLD. There are no differences in these two bullets. We simply designate each one for their particular lines to help shooters use choose bullets for their disciplines. Please let me know if you need anything further. Have a great day!"

"In regards to all of our other Target and Hunting bullets the Target bullets have a thicker jacket to withstand rougher conditions. However, the only bullet in the entire Berger line that is exactly the same in every way in both the Target and Hunting version is the 25 cal 115 gr VLD. There are no differences in these two bullets. We simply designate each one for their particular lines to help shooters use choose bullets for their disciplines. Please let me know if you need anything further. Have a great day!"

The Dust has settled, the Wind has slowed, the Sun Is Up Again!

JT,
Thanks much for posting that. I purchased three boxes of the .257 Target Berger bullets under the assumption they would have the thicker jacket. I wanted to see if they would withstand 3900 fps launches from my 25 RUM. I haven't shot any of them yet, and now I know there's no need to waste barrel life on them. Because about 15% of the Hunting VLDs were coming unglued during launch. It has a 10 twist barrel.

My best move now may be to purchase some Cutting Edge all copper bullets for this overbore magnum. Won't have to worry about those bullets failing during ignition.

I put it together based on many failure discussions, many years ago.
And nothing has changed with VLDs.

The failure here usually occurs with the combination RPMs and heat produced in achieving them.
Of course a rough barrel don't help either.
While I was watching VLD failures it was obvious that HUNTERS were causing them by far.
That is, hunters using extreme overbore cartridges, that successful target shooters would not be using anyway.

I know they want a good hunting market & VLDs are good hunting bullets.
I never had an issue with VLDs in hunting or target shooting because I payed mind to the limits defined.